Taiwanese Journal of Psychiatry

: 2019  |  Volume : 33  |  Issue : 1  |  Page : 51--52

Quetiapine augmented with escitalopram in treating delusional parasitosis

Hung Chiang1, Pei- Hsin Kao2,  
1 Department of Psychiatry, Chi Mei Medical Center, Tainan, Taiwan
2 Department of Psychiatry, Chi Mei Medical Center; Institute of Clinical Medicine, National Cheng Kung University, Tainan, Taiwan

Correspondence Address:
Pei- Hsin Kao
No. 442, Section 2, Shulin Street, Tainan 702

How to cite this article:
Chiang H, Kao PH. Quetiapine augmented with escitalopram in treating delusional parasitosis.Taiwan J Psychiatry 2019;33:51-52

How to cite this URL:
Chiang H, Kao PH. Quetiapine augmented with escitalopram in treating delusional parasitosis. Taiwan J Psychiatry [serial online] 2019 [cited 2023 Mar 22 ];33:51-52
Available from: http://www.e-tjp.org/text.asp?2019/33/1/51/255138

Full Text

Delusional parasitosis (DP) is a psychiatric syndrome that patients presents themselves with false belief that the body is infested with parasites despite of the absence of medical evidence[1],[2],[3],[4]. DP is typically presented with tactile and visual hallucinations which inorganic materials such as lint and skin debris are perceived as causative origins[2],[3],[4]. The patient often seek dermatological care and refuse a psychiatrist referral.

No consensus exists for the most appropriate treatment. First-generation antipsychotic drug (FGA) pimozide was once considered the first-line treatment, which later being substituted by second-generation antipsychotics (SGAs)[1],[3],[4]. Recent studies of selective serotonin reuptake inhibitors (SSRIs) have also shown successful results[5]. Here, we report a case of a female DP patient who was treated successfully with a combination of quetiapine and escitalopram.

 Case Report

A 55-year-old divorced female patient was transferred from medical to psychiatric inpatient ward after she attempted to commit suicide with an herbicide. She had been living alone and having a hard life working at a factory for 18 years. Except for dysthymic mood, she did not have delusions or other psychotic symptoms. Six months ago before the hospitalization, she developed delusion of “infestation of worms.” She reported seeing red and needle-like, black and curl worms, moving at the back of her washing machine. She stated that worms burrowed in her mouth, throat, ankle, and nails, causing crawling, and itching sensation. She had multiple excoriations and wounds from scratching. She also complained that the worms drained her blood in the veins and sucked her urine. The patient had visited several clinics seen by dermatologists and family practitioners, but the symptoms were persisting despite her efforts to remove the worms by picking or using pesticide. She had depressed mood, hyporexia, insomnia, feeling of hopelessness and helplessness, and attempted suicide. Consequently, she was hospitalized on medical intensive care unit.

The patient received laboratory examination, showing the finding of hyperglycemia, which had been under medical control. The brain computed tomography showed the finding of unremarkable lesions. We began to treat her with the dosage of quetiapine 300 mg/day, and slowly titrated the dosage to 900 mg/day. Although symptoms of depression, tactile hallucinations, and itching sensation were improved, by the time of discharge, she achieved only partial remission of psychosis after a five-week inpatient treatment. During follow-ups at outpatient clinic, her quetiapine dosage was titrated to 1,200 mg/day with still little progress in psychosis; thus, we added on escitalopram 10 mg/day on top of quetiapine for nine months. Surprisingly, she improved remarkably without itching, pain, somatic delusion, or visual hallucinations when the dose was reached to 20 mg in the following three weeks.


Since both serotonin and dopamine are implicated to contribute to delusion and hallucinations of DP, SGAs which have effects on both in 5-HT2 and D2 receptors, are reasonable treatment options[2]. Many recent studies have reported favorable outcome for DP with concurrent use of SSRIs, as they modulate serotonin system more specifically and thus produce the augmentative effect[2]. SGAs have opposite effects with SSRIs in 5-HT receptors, so other mechanisms contributing to the valid treatment should be considered. One study has investigated in the effects of SSRIs in mice, on the established sensitization induced by methamphetamine, and the results proposed that SSRIs can be useful in preventing the recurrence of psychosis[6].

Several studies exist to discuss different combinations of antipsychotics and antidepressants[5]. We first used the combination of quetiapine and escitalopram. In our case, the patient did not respond to quetiapine monotherapy but achieved satisfying symptom remission after adding on escitalopram. Their synergistic activity at serotonergic receptors may be the cause of the positive clinical outcome in our patient, and this observation agrees with other clinical reports implicating serotonergic dysfunction of DP[5]. We might also construct simply that our patient had major depressive disorder with psychotic (mainly delusional) feature. However, we still suggest that more studies are required to confirm the efficacy of this therapy regimen (This report was approved by the Institutional Review Board of Chi-Mei Medical Center for publication).

 Financial Support and Sponsorship


 Conflicts of Interest

There are no conflicts of interest.


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